The presence of hydrogen sulphide in gas streams can be detrimental to industrial processes, cause corrosion and interference in gas transportation and cause damage to health, safety and the environment. Accordingly, it is advantageous to remove hydrogen sulphide before such gases are transferred, used or vented to the atmosphere depending on the application.
Typically in sour natural gas processing applications the feed gas containing hydrogen sulphide is passed into an acid gas removal unit (AGR) where hydrogen sulphide is absorbed in an amine by a chemical reaction. Acid gases stripped from rich amine containing hydrogen sulphide are sent to a Claus based sulphur recovery unit (SRU), or alternatively may be injected into a depleted zone of the reservoir or a saline aquifer. However, an amine based gas treating process with Claus based SRU is a very costly scheme from both capital expenditure and operational points of view, and acid gas injection could have various issues ranging from potential risks to health and safety to the loss of a valuable product when the market of elemental sulphur is strong.
There is, therefore, a desire to provide an improved gas treatment process and/or apparatus which mitigates at least some of the problems associated with the prior art.